In the pharmaceutical industry and other fields, for example, preparative separation-purification systems utilizing a liquid chromatograph are used to collect samples of a variety of chemically synthesized compounds in order to store those samples in a library or analyze them in more detail. Conventional examples of the preparative separation-purification system are disclosed in Patent Documents 1 and 2.
In those conventional apparatuses, target components are collected from a sample solution as follows. First, target components (compounds) in a sample solution are temporally separated by a liquid chromatograph. The separated target components are then respectively introduced into different trap columns and temporarily captured therein. Subsequently, a solvent is supplied into each trap column to elute the component from the trap column and collect it in a container. Thus, a plurality of eluates each containing one target component at a high concentration is respectively collected in a plurality of containers. These separately collected solutions are then subjected to a vaporizing and drying process to remove the solvent and collect the target components in solid forms.
In such a preparative separation-purification system, a needle is used with a passage inside thereof which allows a liquid to pass through. For example, a cleaning liquid (column cleaning liquid) for washing off impurities other than the target components captured in the trap column flows through the passage of the needle, and a solvent (eluting solvent) for eluting the target components flows through the passage into the washed trap column. A pipe through which the column cleaning liquid is supplied or a pipe through which the eluting solvent is supplied is connected to the base of the needle. The tip of the needle is inserted into a needle port which is provided at the inlet end of the trap column. This connects the pipe and the trap column. Since different liquids are supplied to the different needles, a column cleaning liquid supply needle and an eluting solvent supply needle are separately provided. In order to use a common driving mechanism for the two needles to simplify the system configuration, the needles stand in a base side by side. That is, the single base is driven to move the two needles to a vicinity of a desired trap column, and then the base is moved more precisely to connect a desired needle to the target trap column.
As described above, a column cleaning liquid supply needle and an eluting solvent supply needle are provided. When the needle is disconnected from the trap column, components captured in the trap column and other substances remain in a circumferential portion of the tip of the needle. If the needle with such residual components adhered to its tip is connected to the next trap column, the residual components enter the trap column, which causes a contamination. In view of this, conventionally, every time the supply of a column cleaning liquid or an eluting solvent to a column is finished, the tips of the needles are washed using a needle washing mechanism as shown in FIG. 5.
In the conventional needle washing mechanism shown in FIG. 5, two washing holes 91a and 91b with an upwardly-open opening are provided with a distance therebetween corresponding to the distance between two needles 19a and 19b, so that the two needles 19a and 19b can be simultaneously washed. After a base 40 is driven to insert the needles 19a and 19b into the washing holes 91a and 91b, respectively, a needle cleaning liquid is supplied to the passages provided inside the needles 19a and 19b by the needle cleaning liquid supply means 100. The needle cleaning liquid flows out from the tips of the needles 19a and 19b and fills the washing holes 91a and 91b. Then, the needle cleaning liquid overflows from openings 92a and 92b at the top of the washing holes 91a and 91b, and is collected in a tray which is not shown. This process removes the residual components attached to the circumferential portion of the tips of the needles 19a and 19b. 